October 6, 2004
12:00 PM (EDT)

News Release Number: STScI-2004-29

NASA's Great Observatories May Unravel 400-Year Old Supernova Mystery

Background information useful for exploring this news release:

Kepler History

Four centuries ago, an evening's entertainment was as simple as stepping
out to gaze at the night sky. But among the world's many star watchers one man
stood apart. Johannes Kepler (1571-1630) was a mathematician and physicist
who not only observed, but also sought to explain the celestial dance above.

A rather frail young man, the exceptionally talented Kepler turned to
mathematics and the study of the heavens early on. When he was six, his mother
pointed out a comet visible in the night sky. When Kepler was nine, his father
took him out one night under the stars to observe a lunar eclipse. These events
both made a vivid impression on his youthful mind and turned him toward a life
oriented to the study of astronomy.

Kepler used simple mathematics to formulate three laws of planetary
motion. Kepler's First Law stated that planets move in elliptical paths around
the Sun. He also discovered that planets move proportionally faster in their
orbits when they are closer to the Sun, and this became Kepler's Second Law.
Finally, Kepler's Third Law explained the relationship between the distance of a
planet from the sun and the amount of time it took to orbit the Sun. Together
these laws of celestial mechanics revolutionized astronomy.

"The era in which Kepler lived was one of tremendous upheaval and change," said
Dr. Dan Lewis, curator of the history of science & technology at the Huntington
Library in San Marino, Calif. "Religious leaders were reluctant to relinquish
the idea that the heavens were the perfect creations of God. Talk by astronomers
of a sky filled with objects moving in non-circular orbits and other phenomena
that went against an Earth-centric model threatened their beliefs. As a result,
Kepler and his first wife, Barbara, created a code with which to write letters
to each other so that their correspondence would not put them at risk of
persecution."

Near the end of the sixteenth century, Kepler apprenticed himself to the
astronomical observer Tycho Brahe, who had an observatory on the island of
Hven in Denmark. The somewhat eccentric Tycho, who had lost a portion of his
nose in a duel and replaced the tip of it with a contraption made of gold and
silver, was nevertheless a brilliant astronomer. Kepler absorbed a great deal of
information from his time working for Brahe, and based much of his later
calculations on Tycho's observations. In 1604, Kepler saw the last supernova
observed in our Milky Way galaxy, which he documented two years later in his
book De Stella Nova, published in Prague in 1606. The explosion of the dying
star was initially as bright as Mars and could be seen with the naked eye. This
was indeed good fortune, for the telescope would not be invented for another
five years.

Several observers spotted the supernova on Oct. 9, 1604. Kepler didn't see
it until Oct. 17, due to cloudy skies in his part of the world. But he studied
the event so extensively that it was named after him. The Kepler supernova is
now a remnant. But it is still studied by astronomers, including those of NASA's
three Great Observatories: the Spitzer Space Telescope, Hubble Space Telescope
and the Chandra X-ray Observatory, using infrared light, visible light, and X-rays.

Kepler was deeply driven by a desire to understand the analytical "why" of
astronomy, well beyond the descriptive "what" of his predecessors Ptolemy and
Tycho. He was also guided by a notion of beauty in the structure of the
universe. In his words, "Happy is the man who devotes himself to the study of
the heavens; their study will furnish him with the pursuit of enjoyments."